Method for removing water from workpieces and apparatus therefor

Abstract

A method for removing water from the surface of workpieces, particularly, glass workpieces, by dipping the workpieces into a boiling dewatering bath composed of an organic solvent which is immiscible with water and which contains surface active agents, and subsequently rinsing the workpiece in one or more baths of the pure organic solvent in order to remove the surface active agent. The subsequent rinsing baths may be boiling or at ambient temperature and vapors therefrom as well as from the initial dewatering bath are condensed and collected. An apparatus for carrying out the method is also disclosed.

Having thus described our invention, what is claimed is: 
     
       1. A method for removing water from the surface of a glass workpiece comprising the steps of: (a) dipping the workpiece into a dewatering bath composed of an organic solvent which is immiscible with water and a surface active agent said bath being at the boiling temperature whereby a water layer is formed in the bath;   (b) thereafter rinsing the workpiece in a second bath composed of the pure organic solvent to remove the surface active agent adhering to the surface of the workpiece;   (c) drying the workpiece;   (d) condensing vapors formed from the dewatering bath, removing water therefrom, and returning the water-free condensate to the dewatering bath;   (e) removing the water layer from the dewatering bath;   (f) separating any remaining solvent from the removed water layer and returning said remaining solvent to the dewatering bath and,   (g) separately condensing vapors for the second bath, removing water from said condensed vapors, and returning the water-free condensate to the second bath.   
     
     
       2. The method of claim 1 wherein the second bath is at boiling temperature, and wherein after dipping the workpiece in the second bath, the workpiece is dipped in a third bath composed of the pure solvent at ambient temperature and wherein the workpiece is then subjected to contact with vapors from a fourth bath of the pure solvent which is at the boiling temperature before the workpiece is dried. 
     
     
       3. The process of claim 2 wherein the third bath is subjected to ultrasonic vibration. 
     
     
       4. A method for removing water from the surface of a workpiece comprising the steps of: (a) dipping the workpiece into a dewatering bath composed of an organic solvent which is immiscible with water and a surface active agent said bath being at the boiling temperature whereby a water layer is formed in the bath;   (b) thereafter rinsing the workpiece in a second bath composed of the pure organic solvent to remove the surface active agent adhering to the surface of the workpiece;   (c) then dipping the workpiece in a third bath composed of the pure solvent at ambient temperature; and then   (d) subjecting the workpiece to contact with vapors from a fourth bath of the pure solvent which is at the boiling temperature;   (e) condensing vapors formed from the dewatering bath, removing any residual water from the vapors and introducing the condensed water-free vapors into the second, third and fourth baths;   (f) introducing solvent from the fourth bath into the dewatering bath;   (g) removing the water layer from the dewatering bath; and   (h) separating any remaining solvent from the removed water layer and returning said remaining solvent to the dewatering tank; and   (i) drying the workpiece.   
     
     
       5. An apparatus for removing water from the surface of a workpiece comprising: (a) a dewatering tank having means for heating a solvent contained therein and means for condensing vapors of said solvent;   (b) second, third and fourth rinsing tanks each having means for condensing vapors of solvents contained therein and said second and fourth tank having means for heating a solvent contained therein;   (c) said dewatering tanks further having means for separating solvent from water contained in vapors condensed by the condensing means and returning the separated solvent to the tank and means for separating water from solvent in the tank and returning the water-free solvent to the third tank;   (d) said second, third and fourth tanks having means for collecting vapors condensed from the condensing means thereof, removing water from the condensed vapors and returning the condensed vapors to the third tank.   
     
     
       6. The apparatus of claim 5 wherein second, third and fourth tank have vapor spaces which communicate with one another and wherein each tank possesses a common condensing unit. 
     
     
       7. The apparatus of claim 5 wherein the third tank has means for imparting ultrasonic vibration to the contents thereof. 
     
     
       8. The apparatus of claim 5 wherein the second and third tanks are separated from one another by an overflow weir. 
     
     
       9. An apparatus for removing water from the surface of a workpiece according to the method of claim 5 comprising: (a) a dewatering tank having means for heating a solvent contained therein and means for condensing vapors of said solvent;   (b) second, third and fourth rinsing tanks each having means for condensing vapors of solvents contained therein and said second and fourth tank having means for heating a solvent contained therein;   (c) said dewatering tank further having means for separating solvent from water contained in vapors condensed by the condensing means and returning the separated solvent to the tank and means for separating water from solvent in the tank and returning the water-free solvent to the third tank;   (d) said second, third and fourth tanks having means for collecting vapors condensed from the condensing means, each tank sharing a common condensing means, means for collecting the condensed vapors from the three tanks, distilling the collected condensed vapors and returning them to the third tank.